But thanks to her well-toned abs, the injuries she suffered -- a torn liver and pancreas, some scratches and numerous bruises -- could've been much worse.
"The doctors said someone with my injuries would be sent straight into surgery," the 47-year-old said. "But they told me 'you're fit. Your muscles helped you and saved you from anything worse.'"
Dr. Lisa Callahan, medical director of the Women's Sports Medicine Center at the Hospital for Special Surgery in New York, said the stronger your "musculoskeletal system" is, the more your internal organs will be protected.
But in general, healthy people like Williams are better able to recover from serious injuries because their heart rates tend to be lower, which reduces the risk of internal bleeding.
They can heal faster too because their bodies are better at processing oxygen.
"I'm very grateful for that minute-a-day exercise," Williams said.
